Question

I have an idea for an application which I’m not sure if possible, I’d appreciate your insights:

I’d like to have a ToolBar in my Shell, where every module that is loaded can add its buttons. The Shell will also have content regions that show the modules’ relevant views.
Some modules share the same regions though, is there a mechanism in Prism that can help with removing buttons that are currently irrelevant?
For example, if ModuleA adds “Get Help” button and ModuleB adds “Send Message” button and they share the same region (only one of them is visible at a given time), when ModuleA is visible, I’d like the “Send Message” button temporarily removed – or at least deactivated – from the ToolBar (but back in the same position when ModuleB‘s view is activated).
Does this approach fit when using MVVM?

Thanks.

Answer 1

It is possible with MVVM and prism. I am doing something similar where I have a switchboard of buttons and it will be populated from a list. Each button represents a form and clicking the button obviously opens that form. I created and ISwitchboard interface that each form implements that desires to be part of the Switchboard. Therefore, each ISwitchboard Interface Item implements ShowDialogForm, and a WPF command etc.

It would be too cumbersome for this post to explain all details that you need to do. However, these are the basic principals by which my code works:

1. In my bootstrapper I override the GetModuleCatelog() method to add any modules I wish. Each module represents an application (form) that will be opened from the switchboard and must inherit from an interface I created so the view model knows how to open it or whether to show it when it needs it. You may not need to use the modules for what you want but that’s your design choosing. That said, if your buttons will open applications, you will need modules.

2. My view model then exposes a list of available modules that use my custom interface that have been added using prism. I am able to get the list of modules through the IModuleCatalog interface which I pass into the VM’s constructor. The list is an observable collection. If I want to implement user rights, then I can restrict the list in that way if I wish.

3. My view then has an itemscontrol which binds to the switchboard list. I can present them how I wish from there. I created an item template to be displayed for each item in the list and it is bound to the Command exposed by the SwitchboardItem interface.